部分包覆钢-混凝土钢筋桁架空腹组合梁受剪性能试验研究OA北大核心CSTPCD

To study the shear behavior of partially-encased steel-concrete composite reinforcement truss open-web beams,the scaled models of four composite beams were designed,the C-shaped connecting rod and the X-shaped bar were set on the abdomen and the shear performance was tested with shear span ratio and web opening ratio as parameters.The results show that the reinforcement truss open-web beams present three failure modes:diagonal compression failure,constrained shear compression failure and cable-stayed bond failure when the shear span ratio increases from 1 to 3.When the web opening ratio is the same,the shear capacity of beams decreases significantly and the deformation capacity increases with the increase of the shear span ratio.Compared with the composite beam with the shear span ratio of 1,the shear capacity of the composite beam with the shear span ratio of 2 and 3 is reduced by 23.94％and 44.08％,respectively.The C-shaped connecting rod and the X-shaped bar reach yielding before the web,and the bearing capacity of the web is fully exerted in the later stage of loading.When the shear span ratio is the same,the shear capacity of the composite beam decreases with the increase of the web opening ratio.When the web opening ratio increases from 51.1％to 67.4％,the shear capacity of the composite beam decreases by 8.82％.Combined with the experiment results and JGJ 138-2016'Code for design of composite structures',the calculation method of shear capacity of reinforcement truss open-web beam was proposed based on superposition principle,the calculated results are close to the experimental results.